[LLVMbugs] [Bug 1701] New: lli vs JIT diffs on FCmp::ne with NaN operands
bugzilla-daemon at cs.uiuc.edu
bugzilla-daemon at cs.uiuc.edu
Tue Sep 25 09:12:32 PDT 2007
http://llvm.org/bugs/show_bug.cgi?id=1701
Summary: lli vs JIT diffs on FCmp::ne with NaN operands
Product: new-bugs
Version: unspecified
Platform: PC
OS/Version: Linux
Status: NEW
Severity: normal
Priority: P2
Component: new bugs
AssignedTo: unassignedbugs at nondot.org
ReportedBy: dgu at stanford.edu
CC: llvmbugs at cs.uiuc.edu
Created an attachment (id=1141)
--> (http://llvm.org/bugs/attachment.cgi?id=1141)
LL asm demonstrating the bug on ordered fcmp with doubles != operator
I am using the LLVM 2.0 release.
I am having a little trouble with the fcmp one instruction on doubles only.
For ordered comparisons, the LLVM manual states that true should be returned
iff neither operands is QNAN. ( http://llvm.org/docs/LangRef.html#i_fcmp)
If I do fcmp one which includes one or both operands as a NaN, the result is
expected to be 0 then.
If I run the bitcode with lli (JIT off), no problem. If I use the JIT (lli
--force-interpreted=true), then it returns 1.
(Converely, fcmp une with the JIT returns 0 instead of the expected 1 ...
without JIT it returns the expected 0).
The other operators (oeq, oge, ..., ueq, uge, ...) seem to work fine.
Is this a bug with the JIT or have I done to muck this up? I've included
source below which illustrates the problem (with doubles on fcmp one only ...
).
Thanks for your help.
~ David
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